Compound engine



(No Model.)

J. B. ROOT. COMPOUND ENGINE.

Patented Apr. 4, 1882.

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UNITED STATES ATENT Osman.

JOHN B. ROOT, OF PORT CHESTER, NEW YORK.

COMPOUND ENGINE.

SPECIFICATION formingpart of Letters Patent No. 256,055, dated April 4, 1882,

Application filed October 9, 1880. (No model.)

To all whom it may concern:

Be it known that I, JOHN B. Root, of Port Chester, in the county of Westchester and State of New York, have invented a new and useful Improvement in Compound Engines, of

I which the following is a specification.

The present invention relates to that class of steam-engines known as compound engines, in which there are two steam-cyliudersone a high and the other a low pressure cylinder the steam being first utilized in the high-pressure cylinder and then passed through an exhaust-port and connecting conduits to the lowpressure cylinder, where it is again utilized, the valves being arranged so that the steam will be admitted on the same side of the pistons of both cylinders simultaneously.

Theinvention has for its object the more perfect, simple, and economical construction of such engines; and it consistsiu,tirst, constructing conduits in the walls of the steam-chest to conduct the steam from the exhaust-port ofthe high pressure cylinder to the lowpressure chest; second, an improved packing for the valve-rod where it passes through the partition of the steam-chests.

The invention is illustrated in the accompanying drawings,in which Figure 1 is a longitudinal central section of the cylinders of an engine. Fig. 2 is a plan view ofthe same. Fig. 3 is a section through the line 00 00 of Fig. 2.

In the drawings, Arepresents the high-pressure cylinder, and B the lowpressure cylinder, of a stealnengine, the body wall or case 0 O of both being preferably formed from a single piece of metal by casting or otherwise.

D is the outer removable head of the cylinder B, and E is a removable partition separating the two cylinders.

F and F are pistons connected to a common rod, G.

H and H are steam-chests, separated by a partition, I. This partition, together with the side and end walls, J J, of the chest may be cast in a single piece.

The cylinders A and B are provided with the usual form of steam and exhaust ports, a and a and b and b, and with sliding valves c,(only one being shown,) attached to a common valverod, (7.

c e are conduits formed in the walls of the chests and connectingwiththeconduitfiformed in the wall of the cylinder A, below exhaustport I), for conveying the steam from the exhaust of the cylinder A to the chest H. The steam enters the chest H through the pipe K, passes alternately down the steam-ports a a, and is exhausted through the port 1) into the conduitf, and thence passes through the conduits e c to the chest I-l, whence it alternately passes down the steam-ports a a, and is exhausted through the port I) and passes out through the pipe L. The sliding valves, of course, are arranged so that corresponding steam-ports of each cylinderthat is, those upon the same side of the pistons-are opened or closed simultaneously.

As it is necessary to obtain access to the dividing-partition E of the cylinders A and B, and sometimes to remove the same for the purpose of adjusting or renewing the piston-packing, this can be done by taking off the head D, unscrewing the nut which secures the pis ton F to the rod G, and removing the piston F through the open end of the cylinder, by which access is gained to the partition E and to the piston-rod packing located in said partition. Whenever it is desired for any purpose to take out the partition E, this can be done by sliding it along the piston-rod and removing it through the open end of the cylinder B. It is, however, desirable that some efficient automatically adjustable packing be used in the opening in the partition E, through which the piston-rod works, so as to render the frequent removal of the parts named unnecessary.

A convenient packing for the valve-rod d, where it passes through the separating partition I of the chests H and H, is illustrated in Fig. 1, and may be formed as follows: A circular aperture of somewhat larger diameter than the rod d is formed through the top plate, N. and extended into the partition I to a plane slightly below the center of aperture through which the valve-rod plays, and at right angles to it. This will leave a space around the half of the surface of the rod next to the top plate which can be supplied with any of the usual packing materials which can be conveniently retained in close contact with the rod and form a tight joint by a close-fitting plate, 1), pressed down by ascrew, r, threaded in the top plate, N.

It will be observed that by casting the body of the cylinders A and B in a single piece the structure is absolutely solid and free from any shake or spring, which is apt to result from separate cylinders when united by the ordinary methods; also, that by bringing the valvesurt'ace of the cylinder A into the same plane with the valve-surface of the cylinder B the entire surface can be planed off at a single operation and form a smooth and level seat for the valves and for the walls and partition of the Slltlll'l-ClltSiS, and so that the valve-stems can be of the same height and the valve-rod be straight, and that by making the partition E removable the piston F can be easily reached and removed and replaced through the cylinder B.

Itis known that. when steam is expanded down to a point below the force of atmospheric pressure the air will rush through the exhaust'pipe andinterfere with theaction of the piston. To remedy this difiiculty I place a-valve in the exhaust-pipe which operates automatically to exclude the air and to permit the steam to pass off. The construction of this valve is illustrated in section in Fig. 3 ofthe drawings, in which 41 represents a valve mounted upon a rod, 8, supported in bearings t t, radiating from the walls of the valve-chamber w. The valve-rod is arranged to slide easily in its bearings, its

outward movement being limited by the abutting ot' a collar, u, or equivalent device formed on the rod against the bearing 25, which leaves the valve in such position that the steam can at all times freely pass it. In the opposite direction the movement of the rod is only limited by the contact of the valve against the walls of its seat q. Itis at once seen that whenever the pressure of the steam acting outwardly is greater than that of the air acting inwardly the valve will be moved away from its seat and the steam will escape, but that whenever the couverse is true the valve will be closed and the air excluded, and the valve will remain closed until the pressure of the accumulated steam is sufficient to overcome the opposing pressure of the air, when the valve will be opened and the steam pass ofi'.

What is claimed as new is 1. In a compound engine, the conduits c 6, formed in the walls of the steam-chest, in combination with the exhaust-port b of the cylinder A, substantially as and for the purpose set forth.

2. In combination with the steam-chests of a compound engine, an aperture partly surrounding the valve-rod d and adapted to receive steam-packing, a plate, 19, and screw 1", substantially as and for the purpose set forth.

JOHN B. ROOT.

Witnesses:

RoB'r. H. DUNCAN, BENJ. A. SMITH. 

